Electronic article surveillance (“EAS”) systems are generally known in the art for the prevention or deterrence of unauthorized removal of articles from a controlled area. In a typical EAS system, EAS tags, markers and labels (collectively “tags”) are designed to interact with an electromagnetic field located at the exits of the controlled area, such as a retail store. These EAS tags are attached to the articles to be protected. If an activated EAS tag is brought into the electromagnetic field or “detection zone,” the presence of the tag is detected and appropriate action is taken, such as generating an alarm. For authorized removal of the article, the EAS tag can be deactivated, removed or passed around the electromagnetic field to prevent detection by the EAS system.
Radio-frequency identification (“RFID”) systems are also generally known in the art and may be used for a number of applications, such as managing inventory, electronic access control, security systems, and automatic identification of cars on toll roads. An RFID system typically includes an RFID reader and an RFID device. The RFID reader may transmit a radio-frequency (“RF”) carrier signal to the RFID device. The RFID device may respond to the carrier signal with a data signal encoded with information stored by the RFID device.
The market need for combining EAS and RFID functions in the retail environment is rapidly emerging. Many retail stores that now have EAS for shoplifting protection rely on bar code information for inventory control. RFID offers faster and more detailed inventory control over bar coding. Retail stores already pay a considerable amount for hard tags that are re-useable. Adding RFID technology to EAS hard tags can easily pay for the added cost due to improved productivity in inventory control as well as loss prevention. Thus, the emergence of combination EAS/RFID tags.
Reusable tags, whether they are EAS, RFID, combination EAS/RFID, or other types of security tags, are typically removed from their articles before the customer exits the store. The security tags are affixed to their article by a locking mechanism such as a clamp that retains an attachment element such as a pin, which prevents the article from unauthorized removal from the store. One type of clamp is a magnetic clamp that can be unlocked by a permanent magnet in a detacher unit. This disengages the attachment pin in the tag to allow the article to be removed.
The locking mechanism (such as a moving clamp or pin) is usually made with a magnetic material such as carbon steel. Upon exposure to a magnetic field from a detacher unit, part of the clamp is attracted to the detacher. This magnetic force is used to unlock the pin from the tag housing thus allowing the item to which the tag was attached to be removed from the store without setting off an alarm. In order to prevent illegitimate tag detachment using a commonly available magnet, the tag's clamp is typically designed such that it can only be opened when exposed to an unusually high magnetic field. Thus, many detacher designers have created detacher units having a magnetic structure that are capable of producing high field strength. However, with the advancement of magnet technology, magnets possessing significant magnetic field strength can be obtained if the shoplifter puts his or her mind to the task. This allows shoplifters to conceal a high powered magnet, enter a store, and use the magnet to detach the.
Therefore, what is needed is a magnetic clamp and detaching arrangement that overcomes the above-described challenges.